A flexible display device is made based on a flexible base material. The flexible display device has advantages of being rollable, wide view angle, and good portability, and thus has a broad application prospect and favorable market potential in many display application fields, such as portable products.
Conventionally, an array substrate in the flexible display device includes an insulation layer, such as an inorganic buffer layer, a gate insulation layer, an inter-layer insulation layer and a passivation layer. The above insulation layer is usually made of a material of SiNx or SiOx which has a poor tenacity. Thus, the insulation layer is prone to be broken when the flexible display device is being bended, and thereby the reliability of thin film transistors (TFTs) and storage capacitors on the array substrate of the flexible display device is degraded or even damaged. As a result, a reliability of the display device is dissatisfying.